Overview and planning of z/OS Batch Runtime

In today's z/OS® environment, many installations want to re-engineer their existing native z/OS PL/I, COBOL, and Java™ applications to incorporate the Java language. By doing so, they can keep their heritage of existing z/OS PL/I, COBOL, and Java batch applications, while taking advantage of the larger developer skill base and many language features of Java. As such, there is a requisite need to share a local DB2® for z/OS attachment across the PL/I, COBOL, and Java language boundary. This enables mixed language programs to process DB2 for z/OS requests in the same unit of work (UOW). When these batch application suites are re-engineered or updated, they should also allow transparent local DB2 for z/OS access from PL/I, COBOL, and Java to the following programs:

Embedded Structured Query Language (SQL) DB2 access, which is used in Enterprise PL/I, COBOL, and Java
Java Database Connectivity (JDBC) for Dynamic SQL
Embedded Structured Query Language for Java (SQLJ)

z/OS Batch Runtime allows for this interoperability between PL/I, COBOL, and Java applications that run on z/OS. It is a program designed to provide a managed environment that enables shared access to a DB2 connection by PL/I, COBOL, and Java programs. Updates to DB2 are committed in a single transaction. (Note that updates to multiple databases are not supported.)

A new feature of z/OS Batch Runtime is support for the IBM® Java Batch Programming Model. It enables pure Java batch applications to be both data source and sink neutral with an XML like definition and is fully described in Appendix A. A new JCL statement, //BCDXJCL is added as the source for this descriptor along with a new and special language type, XJCL.

Figure 1 shows a high-level overview of the z/OS Batch Runtime environment. The batch container performs the initialization that sets up the environment for PL/I, COBOL, Java, and DB2 interoperability. This includes the following tasks:

Setting up the proper Language Environment® for the PL/I or COBOL programs to run
Setting up the job step under the umbrella of a Resource Recovery Services (RRS)-managed global transaction
Initiating the DB2 JDBC driver in this special “BatchContainer” mode
Invoking the DB2 JDBC driver to create a DB2 connection and attachment thread
Invoking the primary PL/I, COBOL or Java application after the environment is properly initialized.

Figure 1. Overview of the z/OS Batch Runtime environment